Prevalence of Probable REM Sleep Behavior Disorder in Essential Tremor

Essential Tremor (ET) has traditionally been regarded as a pure motor disorder. However, emerging evidence suggests associations with non-motor symptoms, including cognitive impairment, psychiatric disturbances, and sleep abnormalities. REM Sleep Behavior Disorder (RBD) is a known prodromal feature of alpha-synucleinopathies such as Parkinson's disease (PD). The relationship between ET and RBD remains unclear, with previous studies reporting variable prevalence rates.

This study aimed to determine the prevalence of probable RBD (pRBD) among patients with ET using the REM Sleep Behavior Disorder Single-Question Screen (RBD1Q).

In this single-center, cross-sectional study, we identified ET patients from the Parkinson's Disease Center and Movement Disorders Clinic at Baylor College of Medicine. Eligible patients were contacted and screened for pRBD using the RBD1Q. A small cohort of healthy controls, including spouses, was also screened. Demographic and clinical characteristics were compared between ET patients with and without pRBD.

Among 245 ET patients, 21.2% screened positive for pRBD. There were no significant differences in age, age at tremor onset, or tremor duration between patients with and without pRBD. There was a significantly higher percentage of males among ET patients with pRBD (63.5% vs. 48.7%, p = 0.045).

In this study, pRBD screen positivity was relatively more common in ET patients than historical controls. These findings suggest that sleep-related symptoms may be relevant in ET and support further study with polysomnographic confirmation of RBD and longitudinal follow-up of these symptoms in ET patients.